1. Field of the Invention
The present invention relates to a printing apparatus, a method for controlling the printing apparatus, and a storage medium, and in particular, to a printing apparatus, a method for controlling the printing apparatus, and a storage medium that suppress a print position shift due to a change in friction coefficient between a print medium and a conveying unit.
2. Description of the Related Art
In a printing apparatus, an image is printed on a print medium by applying a color material on the print medium from a print head and conveying the print medium. An example of the conveying system of the print medium includes a roller conveying system of nipping and conveying the print medium between a conveying roller and a pinch roller driven thereby, and the like. In addition, some of the printing apparatuses perform a double-sided print in which an image is printed on one surface (hereinafter, referred to as “front surface”) of the print medium and then, an image is printed on the other surface (hereinafter, referred to as “back surface”) thereof.
In the double-sided print, in the case where there occurs a change (extension/contraction or the like) in state of the print medium due to application of the color material on the front surface at the printing thereon, in some cases a difference occurs in an image size between the front surface and the back surface. For prevention of this occurrence, a printing apparatus disclosed in Japanese Patent Laid-Open No. 2011-121237 estimates a change amount of the print medium based upon image data of the front surface and corrects at least one of the image data of the front surface and the image data of the back surface based upon the estimated telescopic amount.
At the double-sided printing, in the case where a change in the state of the print medium occurs by printing an image on the front surface, a friction coefficient between the print medium and the conveying roller changes between the printing time of the front surface and the printing time of the back surface to change a conveying force of the conveying roller, and therefore the conveying speed of the print medium may change. As a result, there are some cases where the print position is shifted from a desired position at the back surface printing after the front surface printing.
In the printing apparatus according to Japanese Patent Laid-Open No. 2011-121237, the extension/contraction of the print medium is estimated to correct the image data, and thereby the dimension difference between the front and back-surface images is suppressed. Therefore in some cases it is not possible to appropriately suppress the print position shift at the back surface printing after the front surface printing due to the change in conveying speed of the print medium caused by the change in friction coefficient between the print medium and the conveying roller.